383 harmonic damper

The 383 cast crank IS INTERNALLY balanced even though it is cast ,same as the 318 cast crank IS INTERNALLY balanced. U do not need any counter weighted balancer or flex plate or fly wheel. If your crank is indeed a 383 cast it is outta a 1971 383, G code for 71....as A=65,b=66 c=67,d=68,e=69 f=70.U can tell by the parting line wide flat approx 1/2 in wide=forged....narrow like a jagged1/6=cast.Hopes this help u guys out. If I can be of anymore help to u , just PM me or by e-mail.....Thanks........Kim